Acanthosis nigricans (AN) is characterized by velvety hyperpigmented thickening of the skin, most often over posterior neck, axillae, and groin. This cutaneous finding is common in obese children, and usually associated with insulin resistance and hyperinsulinemia. It has been hypothesized that increased binding of insulin to insulin-like growth factorI (IGF-1) receptors on keratinocytes may lead to AN, augmented by action of epidermal growth factor(EGF). We will investigate expression of receptors for IGF-1 and EGF in AN lesions & normal skin from patients with AN.